عنوان مقاله [English]
Rainfall is a climatic element that changes year by year, and in fact rainfall is a random variable over time. If the long-term rainfall data are available, the probability of occurrence of precipitation can be determined by statistical methods.
In this study, the city of Semnan has been selected in order to determine the probability of annual, seasonal and monthly precipitation. Precipitation data in this city have been analyzed using computer software and statistical methods. Wet and dry periods, seasonal and monthly variations in precipitation and the probability of occurrence of seasonal and monthly precipitation have been determined.